With evolution of a transistor manufacturing process, a transistor size becomes smaller. However, in a process of reducing the transistor size to near a physical limit, there are many problems with the transistor, such as serious short channel effect, a big leakage current, and large power density. To resolve these problems, the industry puts forward various solutions. A TFET (Tunneling Field Effect Transistor) attracts wide attention because it has advantages of weak short channel effect, a small off-state current, no limitation by a subthreshold swing of an MOSFET (Metal Oxide Semiconductor Field Effect Transistor), and the like.
FIG. 1 shows an existing tunneling field effect transistor. For a tunneling field effect transistor of this structure, in a manufacturing process, ion injection of different types is performed on a source region and a drain region separately. To increase a tunneling current, a gate region and the source region are partially overlapped (as shown by A in FIG. 1) in the manufacturing process. Under an action of a gate electric field, band-to-band tunneling occurs on a carrier, thereby producing a channel current. In the tunneling field effect transistor with a line tunneling working mechanism, a carrier tunneling direction is parallel to a gate electric field direction, a gate control capability is relatively strong, and a tunneling current magnitude may be regulated according to an overlapping area of the gate region and the source region.
In the prior art, the source region and the drain region of the tunneling field effect transistor are doped with impurities in an ion injection manner. However, impurity concentration distribution formed in the source region and the drain region in an ion injection process is generally Gaussian distribution. Therefore, when the ion injection process is used, ions are not evenly distributed, and a tunneling junction with mutant doping is difficult to form. Under an action of a specific gate electric field, carrier tunneling efficiency is relatively low.